Highly alkali-stable poly(arylene alkylene piperidinium) cationic polymers and preparation methods and applications

Abstract

The present invention relates to the field of cationic polymers, and in particular, to highly alkali-stable poly(arylene alkylene piperidinium) cationic polymers and preparation methods and applications. The preparation method for the highly alkali-stable poly(arylene alkylene piperidinium) cationic polymers includes the following steps: performing catalytic polycondensation on 1-R 6 -piperidine-3-carboxaldehyde or a salt or hydrate thereof and an aromatic compound to obtain a polymer having a piperidine moiety; and then further subjecting the polymer to a quaternization reaction to obtain the poly(arylene alkylene piperidinium) cationic polymer. The anion exchange membranes prepared from the piperidinium-based cationic polymers have ultra-high alkaline stability and excellent mechanical properties and ionic conductivities, and can be applied to the fields of electrochemical energy conversion such as fuel cells, hydrogen production by water electrolysis, electrochemical reduction of carbon dioxide, flow batteries, and fields of separation such as electrodialysis and water treatment.

What is claimed is: 
     
         1 . Alkali-stable poly(arylene alkylene piperidinium) cationic polymers, comprising the following structural subunits: 
       
         
           
           
               
               
           
         
         wherein R 1  is selected from an H atom or a hydrocarbyl group with 1-20 carbon atoms, or wherein both R 1  groups are connected to each other to form a cycloalkyl group consisting of 4 to 10 carbon atoms; and wherein the counterion A −  is selected from one or more of halide ions, methyl sulfate ions, hydroxide ions, or bicarbonate ions; and 
         wherein the Ar′ unit is selected from one or more of the following structures: 
       
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         2 . The alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 1 , further comprising one or more of the following structural units: 
       
         
           
           
               
               
           
         
         wherein k=0 or 1; and x=0-12; 
         R 2  is independently selected from a hydrogen atom, a hydrocarbyl group with 1-20 carbon atoms, or a fully or partially fluorinated alkyl group with 1-6 carbon atoms; 
         Q′ is selected from one or more of H, —N + (R 5 ) 3 , or a nitrogen heterocycle-containing cationic group, and the counterion A −  is selected from halide ions, methyl sulfate ions, hydroxide ions, and bicarbonate ions; and 
         wherein R 3  is selected from an H atom or a hydrocarbon group with 1-20 carbon atoms, or wherein both R 3  groups are connected to each other to form a cycloalkyl group consisting of 4 to 10 carbon atoms; 
         wherein R 4  is selected from an H atom or a hydrocarbon group with 1-20 carbon atoms, or wherein both R 4  groups are connected to each other to form a cycloalkyl group consisting of 4 to 10 carbon atoms. 
       
     
     
         3 . A preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 2 , comprising the following steps:
 S1, mixing 1-R 6 -piperidine-3-carboxaldehyde or its salt or hydrate thereof with aromatic compounds to obtain a polymerization compound mixture, placing the polymerization compound mixture in a first organic solvent, and adding a strong organic acid for catalytic polycondensation to obtain a polymer dispersion with piperidine moieties;   S2, slowly dropping the polymer dispersion with the piperidine moiety in the S1 into a first precipitant, filtering, washing, and drying to obtain a polymer powder with piperidine moieties;   S3, dissolving the polymer powder with the piperidine moieties in the S2 in a second organic solvent to obtain a mixture, adding quaternization reagents into the mixture, obtaining a cationic polymer solution after a quaternization reaction at 0-100° C. for 0.1-100 h; and   S4, slowly adding the cationic polymer solution in the S3 into a second precipitant, filtering and drying the filtered precipitate to obtain a poly(arylene alkylene piperidinium) cationic polymer powder.   
     
     
         4 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 3 , wherein in S1, a structural formula of 1-R 6 -piperidine-3-carboxaldehyde is shown as follows: 
       
         
           
           
               
               
           
         
         wherein, in the formula, R 6  is selected from one or more of an H atom or a hydrocarbyl group with 1-20 carbon atoms. 
       
     
     
         5 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 3 , wherein in S1, the polymerization compound mixture further comprises carbonyl monomers, and the carbonyl monomers have one or more of the following structures: 
       
         
           
           
               
               
           
         
         wherein, in the formula, k=0 or 1; x=0-12; 
         Q is selected from one or more of an H atom or a halogen atom; 
         R 7  is selected from one or more of an H atom, a hydrocarbyl group with 1-20 carbon atoms, or fully or partially fluorinated alkyl groups with 1-6 carbon atoms; and 
         wherein R 8  and R 9  are each independently selected from an H atom or a hydrocarbyl group with 1-20 carbon atoms. 
       
     
     
         6 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 3 , wherein in S1, the molar ratio of the 1-R 6 -piperidine-3-carboxaldehyde or a salt or hydrate thereof to the strong organic acid is 1:(1-20). 
     
     
         7 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 5 , wherein in S1, the ratio of the sum of the molar amounts of 1-R 6 -piperidine-3-carboxaldehyde or a salt or hydrate thereof and carbonyl monomers to the molar amounts of strong organic acid is 1:(1-20). 
     
     
         8 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 3 , wherein in S3, the quaternization reagent is dimethyl sulfate or halogenated hydrocarbons with 1-20 carbon atoms having a structure of: 
       
         
           
           
               
               
           
         
         wherein R 101 , R 102 , R 103 , and R 104  are each independently selected from hydrogen, halogen, hydrocarbyl groups or halohydrocarbyl groups with 1-20 carbon atoms, or aryl groups or halogenated aryl groups with 1-20 carbon atoms, and the halohydrocarbyl groups or halogenated aryl groups contain at least one halogen atom. 
       
     
     
         9 . The preparation method for the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 3 , wherein the poly(arylene alkylene piperidinium) cationic polymer powder in S4 is immersed in a solution containing other types of counterions for ion exchange to obtain a cationic polymer containing other types of counterions. 
     
     
         10 . A method of use of the alkali-stable poly(arylene alkylene piperidinium) cationic polymers according to  claim 2 , wherein an alkali-stable poly(arylene alkylene piperidinium) cationic polymer is applied to an anion exchange membrane or a catalyst layer binder.